PARIS — Islamist militants seized a foreign-operated gas field in Algeria early Wednesday and took at least 20 foreign hostages, including Americans, according to an Algerian government official and the country’s state-run news agency, in what the attackers called a retaliation for the French-led military intervention in neighboring Mali.
The Algerian agency said at least at least two people had been killed in the gas-field seizure, including one British national, and that the hostages included US, British, French, Norwegian and Japanese citizens.
Victoria Nuland, a US State Department spokeswoman, told reporters in Washington that, ‘‘the best information that we have at this time is that US citizens are among the hostages.’’
The exact number of people being held was still far from certain. A top Algerian government official said security services had now ‘‘encircled the base’’ so that ‘‘no one can leave.’’ But he added that ‘‘the situation is confused for the moment. We don’t have precise figures for now. Maybe 30’’ hostages in all.
As for the attackers, he said, ‘‘There were 20 of them, in three vehicles, heavily armed. They came in vehicles that were unmarked, that’s how they slipped through.’’
Other news agencies said as many as 41 hostages were seized.
The attack on the gas field is the first known retribution by the Islamists for the French armed intervention in Mali last week and raised the possibility of drawing an increasing number of foreign countries directly into the conflict.
A Japanese official confirmed that Japanese nationals were involved, and the Irish Foreign Ministry said one Irish citizen had been kidnapped. The Sahara Media Agency of Mauritania, quoting what it said was a spokesman for the militants, said they were holding five hostages in a production facility on the site and 36 others in a housing area, and that there were as many as 400 Algerian soldiers surrounding the operation. But that information could not be confirmed, and the agency’s report on the specifics of where the hostages were held raised questions about its credibility.
Fighters with links to Al Qaeda’s African affiliate, Al Qaeda in the Islamic Maghreb, claimed responsibility for the attack, according to both Mauritanian and Algerian news agencies. They quoted militants claiming that the kidnappings were a response to the Algerian government’s decision to allow France to use its airspace to conduct strikes against Islamists in Mali.
Islamist groups and bandits have long operated in the deserts of western Africa, and a collection of Islamists have occupied the vast expanse of northern Mali since last year. In retaliation for the French-led effort to drive them out, those groups, including Al Qaeda in the Islamic Maghreb, have pledged to strike against France’s interests on the continent and abroad, as well as those of nations backing the French operations. In France, security has been reinforced at airports, train stations and other public spaces.
The militant groups are financed in large part through ransoms paid for the freeing of Western hostages, and regular kidnappings have occurred in the West African desert in recent years. Seven French nationals are presently being held there.
The attack Wednesday was carried out by a ‘‘heavily armed’’ group of ‘‘terrorists’’ traveling aboard three vehicles, the Algeria Interior Ministry statement said, and targeted a bus transporting foreign workers to a nearby airport at 5 a.m. An ‘‘indeterminate number’’ of hostages were taken, the ministry said, while one foreigner was killed and six people were wounded, including two security guards and two police officers.
A member of the Algerian parliament said four Japanese and one French national were kidnapped, Agence France-Presse reported.
The gas field in In Amenas is a joint venture operated by the British multinational BP, the Norwegian group Statoil and the Algerian government-owned Sonatrach. The Japanese engineering firm JGC provides services there.
BP confirmed a ‘‘security incident’’ had occurred at the gas field and said in a statement that it was arranging an emergency information line for relatives. The British Foreign Office said in a statement that ‘‘we can confirm that British nationals are caught up in this incident.’’
Algeria, which shares a desert border of several hundred miles with Mali, has resisted the possibility of organizing an armed intervention into the Malian north, fearing that fighting could spill into Algeria or drive militants into the country. Algeria has authorized French jets flying missions in Mali to cross Algerian airspace, however.
Al Qaeda in the Islamic Maghreb began as an insurgent group fighting the secular Algerian government in the 1990s.